diff options
| -rw-r--r-- | drivers/platform/x86/dell-wmi.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c index 1ad7a7b41574..5db9efbde5b9 100644 --- a/drivers/platform/x86/dell-wmi.c +++ b/drivers/platform/x86/dell-wmi.c @@ -237,6 +237,22 @@ static void dell_wmi_notify(u32 value, void *context) buffer_end = buffer_entry + buffer_size; + /* + * BIOS/ACPI on devices with WMI interface version 0 does not clear + * buffer before filling it. So next time when BIOS/ACPI send WMI event + * which is smaller as previous then it contains garbage in buffer from + * previous event. + * + * BIOS/ACPI on devices with WMI interface version 1 clears buffer and + * sometimes send more events in buffer at one call. + * + * So to prevent reading garbage from buffer we will process only first + * one event on devices with WMI interface version 0. + */ + if (dell_wmi_interface_version == 0 && buffer_entry < buffer_end) + if (buffer_end > buffer_entry + buffer_entry[0] + 1) + buffer_end = buffer_entry + buffer_entry[0] + 1; + while (buffer_entry < buffer_end) { len = buffer_entry[0]; |